All these recipes are made up to 1 litre with distilled water unless otherwise stated. Most of these media can be made up as broths by omitting the agar.
Media for bacteria
Nutrient agar
Beef extract l0 g
Peptone l0 g
NaCl 5 g
Agar 20 g
Adjust the pH to 7.4 before autoclaving.
Milk agar (for milk bacteria)
Make up nutrient agar as above, but using only 900 mL of water. Dissolve 20g of dried skimmed milk in 100 mL of water. Autoclave separately. Mix together aseptically once the liquids have cooled to 45–50 °C.
Acetobacter broth (for Acetobacter aceti)
Yeast extract 5 g
Malt extract 10 g
Dissolve in 1 litre of water, autoclave, then add 30 mL of ethanol once cool.
Dissolve the above in 250 mL distilled water, then add 750 mL of sea water (use artificial sea water from school science suppliers or an aquarist’s shop). Autoclave and dispense as usual. 15 g of agar can be added to make a solid medium if required.
Vibrio natriegens broth (Suitable for growth experiments)
Nutrient broth 13 g
NaCl 20 g
After autoclaving, adjust pH to 7.5. For a solid medium, add 15 g of agar. Note: this recipe is a suitable alternative to Heart–Brain infusion broth.
Recipes for growth media
All these recipes are made up to 1 litre with distilled water unless otherwise stated. Most of these media can be made up as broths by omitting the agar.
Media for bacteria
Nutrient agar
Adjust the pH to 7.4 before autoclaving.
Milk agar (for milk bacteria)
Make up nutrient agar as above, but using only 900 mL of water. Dissolve 20g of dried skimmed milk in 100 mL of water. Autoclave separately. Mix together aseptically once the liquids have cooled to 45–50 °C.Acetobacter broth (for Acetobacter aceti)
Dissolve in 1 litre of water, autoclave, then add 30 mL of ethanol once cool.
Mannitol yeast extract agar (for Rhizobium)
Photobacterium broth (for Photobacterium phosphoreum)
Dissolve the above in 250 mL distilled water, then add 750 mL of sea water (use artificial sea water from school science suppliers or an aquarist’s shop). Autoclave and dispense as usual. 15 g of agar can be added to make a solid medium if required.
Vibrio natriegens broth (Suitable for growth experiments)
After autoclaving, adjust pH to 7.5. For a solid medium, add 15 g of agar. Note: this recipe is a suitable alternative to Heart–Brain infusion broth.
Methylophilus broth (for Methylophilus methylotrophus)
Trace metal solution (per litre)
Sterilize by autoclaving before adding 0.5% by volume of methanol. 15 g of agar can be added if a solid medium is required.
Media for fungi
Potato dextrose agar (for mould fungi)
This can be made using reconstituted dried potato or boiled and peeled fresh potatoes.
Malt Extract Agar (for fungi)
Yeast complete medium (suitable for Saccharomyces spp.)
Tributyrin agar (for the detection of lipase activity)
Starch agar (for the detection of amylase activity)
Dissolve the above in 900 mL water. Dissolve 2 g starch in 100 mL hot water. Add to the mineral solution. Autoclave and dispense as usual.